The relationship between dayside and nightside Dynamics under northward interplanetary magnetic field substorms

Substorms that occur under northward interplanetary magnetic field (IMF) conditions can elucidate the relationship between the dayside and nightside dynamics of the ionosphere. We investigate the relationship between the dayside and the nightside dynamics in response to northward IMF substorms. While the dynamics of the dayside ionosphere are directly related to the interaction between the solar wind interplanetary magnetic field (IMF) and the earth’s magnetic field, the dynamics in the nightside are strongly controlled by magnetotail activity like substorms. Under southward IMF conditions, both reconnection on the dayside and substorms on the nightside increase Dungey convection, making it difficult to distinguish the separate contributions of dayside and nightside processes to large-scale dynamics. Under northward IMF conditions, on the other hand, it is easier to distinguish between dayside and nightside processes, since northward IMF does not increase Dungey flows. We present a superposed epoch analysis of the equivalent current and magnetic perturbations above 60 deg magnetic latitude (mlat) from ground-based magnetometer stations based on 280 northward IMF substorms. We also investigate whether the dayside current pattern is influenced by the substorm onset.